The present invention relates to a testing device, and more particularly, to a cradle and cable handler for a test head manipulator.
U.S. Pat. No. 5,931,048 to Slocum, which is included for all of its teachings by reference, describes a test head positioner or manipulator that includes a cradle (FIG. 6 of '048) for holding a test head. Mechanisms within this cradle allow the test head to be moved in directions (defined in FIG. 2 of '048) In-Out, Nod Up-Down, and Theta Left-Right. (Nod motion may also be referred to as pitch or tumble elsewhere in the literature and herein. Theta motion may sometimes be referred to as yaw motion elsewhere in the literature and herein.) Each of the two sides of the test head is coupled to one of two cradle arms. A motorized actuator is provided in each of the two cradle arms to move that arm's test head coupling linearly along the arm. If the two actuators move their respective coupling in the same direction, In-Out motion is achieved. If the two actuators move their respective couplings in opposite directions, Theta Left-Right motions are achieved. The motor driven actuators include clutch mechanisms. With the clutches disengaged, a relatively small external force may be applied to move the test head slightly with respect to the cradle. This provides compliance to enable a test head dock to finely position the test head with respect to a test peripheral such as a package handler or wafer prober. This is a relatively complex and expensive solution in that it requires electromagnetic components and a controller to coordinate the motions of the two actuators. The '048 patent also identifies that the handling of the cable that connects the test head to a mainframe is difficult and complicates smooth positioning of the test head. As cables become increasingly large and awkward due to the inclusion of more conductors, air ducts for cooling, and hoses and tubing for conveying liquid coolants, this problem has grown increasingly difficult.